Nearly three in four maternal healthcare professionals say heat-related complications among pregnant women have increased over the past five years, according to a survey released on Monday as climate ministers gathered in Fiji for the last major ministerial meeting before COP31. Some 76 per cent, reported an increase in heat-related problems affecting foetal or newborn health.
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The survey of 1,000 maternal healthcare professionals in Australia, Brazil, India, the UK and Zimbabwe, commissioned by global health foundation Wellcome, found that almost all respondents had cared for a pregnant woman (98 per cent) or a baby (99 per cent) whose health they believed had been affected by extreme heat. Simon Stiell, the UN’s climate chief, presented the findings on the opening day of Pre-COP, which runs until 8 October.
Stiell said women most exposed to the risks work outdoors, live in poorly built housing or give birth in clinics without reliable power or cooling. Researchers have warned that the risks are likely greatest in poorer countries, yet most research on heat and pregnancy has been conducted in wealthier ones.
“‘Staying cool’ is simply not an option when there is no cool place to go,” Stiell said in his speech. “A safe birth is already too often shaped by geography, income and access to care. Without action, extreme heat will widen that injustice.”
Heat is also making it harder to access care, respondents said. Just over a quarter of respondents (27 per cent) said pregnant women and families were finding it more difficult to travel to or access care, and 29 per cent reported an increase in urgent or emergency visits.
Research suggests the odds of preterm birth rise by about 5 per cent for every 1°C increase in temperature, with the risks likely greatest in low- and middle-income countries. Image: Wellcome.
Disproportionate risk
The survey, conducted online by the research firm Censuswide with 200 respondents in each country between 17 September and 1 October 2026, records the experience of maternity healthcare workers, rather than measured outcomes of the patients.
Its findings are, however, consistent with a growing body of clinical evidence. A 2020 analysis in medical journal The BMJ found that the odds of preterm birth rose by 5 per cent for every 1°C increase in temperature, and by 16 per cent during heatwaves. The authors noted that the risks might be largest in low- and middle-income countries.
A broader 2024 review in Nature Medicine, which pooled 198 studies from 66 countries, estimated the increase in the odds of preterm birth at 4 per cent per degree, and found that the odds of any obstetric complication rose by a quarter during heatwaves. Most of that research, however, has been done in wealthier countries; 63 per cent of the studies in the Nature Medicine review came from high-income nations.
The risks also vary within wealthier countries. A study of 53 million births across 50 US metropolitan areas between 1993 and 2017, published in JAMA Network Open, found that preterm and early-term births rose after heatwaves, particularly among socioeconomically disadvantaged groups.
92 per cent of survey respondents said they wanted more training and resources to protect pregnant women during extreme heat. Some of the measures being tested are simple ones; a Wellcome-funded study in South Africa and Zimbabwe, known as HAPI, is trialling handheld fans, reflective paint on the roofs of health facilities and community-led climate information systems.
Bridging the funding gap
Expanding these measures across health systems will require additional funding. The UN Environment Programme estimates that developing countries will need US$310–365 billion a year for adaptation by 2035, while international public adaptation finance to those countries fell to US$26 billion in 2023, from US$28 billion a year earlier.
The World Health Organization estimates that only about 0.5 per cent of multilateral climate finance has gone to health. At COP30 in Belém last year, countries called for adaptation finance to be tripled, but by 2035 rather than the 2030 deadline that climate-vulnerable nations had sought.
Madeleine Thomson, head of climate impacts and adaptation at Wellcome, said many of the solutions to protect people were already known. “But the challenge is providing solutions to those who need them most, including pregnant women and newborns, who face serious risks but often receive inadequate information and support,” she said.
Wellcome and its partners are calling for pregnant women and newborns to be included in national climate and health plans before COP31, which opens in Antalya, Türkiye, on 9 November. Stiell said in his speech that that “a newborn’s healthy start must never depend on a family’s ability to escape the heat”.
